First post, by dinth
Hi. I am trying to build a 486 computer, using my older motherboards and they all seem to be dead, but when i tried a third one is completely dead it started to feel unlikely.
For powering it i have bought a 150W ATX power supply (https://www.amazon.co.uk/gp/product/B09B2739V … e?ie=UTF8&psc=1), and a converter to AT. I hooked it up to a power supply tester and everything is all right.
I have dug out a couple of old graphic cards, one Virge and one ET3000.
I also purchased a tested Intel DX4/100 CPU online.
I have also bought an ISA POST tester (https://www.amazon.co.uk/gp/product/B07B65PBR … e?ie=UTF8&psc=1)
The first two motherboards i have tested had leaky batteries and some damage caused by them. All the caps looked all right though. After hooking them both looked completely dead - no beeps, no VGA output (i tried both cards with every mobo) and above anything else no POST codes on the ISA post tester.
The third motherboard has a ODIN encased battery, which is probably dead too, but no leaks outside and no acid damage anywhere. Caps looking all right too. I hooked everything up and unfortunately im getting same behaviour - no beeps, no VGA output and no POST codes ("----") on the ISA post tester. CPU was getting warm though. I had a look into the manual for the tester and it says that no codes are present when the CPU is dead. So i have purchased a new CPU on ebay, this time a tested AMD 100Mhz, replaced the CPU and still getting the same behaviour - the computer doesnt post but CPU is getting warm.
I dont know what is the model of the motherboard, but seems that CPU jumpers are currently set to 1x 50MHz. Not exactly sure about memory jumpers, but even if those are misconfigured, the motherboard should POST, right?
After powering the mobos, they are taking between 6 and 11W from the power supply, depending on the number of memory modules and if the GPU is inserted
I know that those mobos are super old, but the fact im getting the same issue (no POST, but with CPU powered) on three separate motherboards (which used to work) seems to be somewhat unlikely. Maybe im doing something wrong, or forgetting about something, it has been over 20 years since i last played with 486 gen computer? Could someone please sanity check me?